JPH0389708A - Piezoelectric resonator - Google Patents

Abstract

PURPOSE:To eliminate the need of executing a complicated polarization method, to simplify and miniaturize the constitution of a piezoelectric oscillation circuit by forming resonance electrodes for both sides of a piezoelectric board whose polarization direction is uniform. CONSTITUTION:The piezoelectric board 11 is uniformly polarized. The first and second resonance electrodes 12a and 12b are formed on one main surface, and third and fourth resonance electrodes 12c and 12d on the other main surface. The third and fourth resonance electrodes 12c and 12d are formed so that they face the first and the second resonance electrodes 12a and 1b by two sides. The first-fourth resonance electrodes 12a-12d are led out to the outer peripheral side of the piezoelectric board and the first-fourth terminal electrodes 15a-15d are respectively formed on the side of the piezoelectric board 11. Then, the third terminal electrode 15c and the second terminal electrode 15b are electrically connected by using the outer peripheral surface of parts. Thus, a complicated polarization and external wiring work are not required, and a small and inexpensive piezoelectric resonator incorporating load capacity can be obtained.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a chip-type piezoelectric resonator using an energy confinement type piezoelectric resonator, and in particular, a resonant electrode and an extraction structure of the resonant electrode are improved. related to things.

[Conventional technology]

As a Colpitts-type oscillator circuit using a piezoelectric oscillator, the second
The circuit shown in the figure is known. In FIG. 2, l is an inverter, 2 is a feedback resistor, 3 is a piezoelectric resonator, and 4 and 5 are external capacitors.

By adjusting the capacitance values of the external capacitors 4 and 5, the oscillation voltage can be controlled to an appropriate value and stable oscillation can be obtained.

However, the above configuration requires an external capacitor, which increases the number of parts. Therefore, a configuration has been proposed in which the external capacitor 4.5 can be omitted (for example, Japanese Patent Laid-Open No. 55-95417). As shown in FIG. , two resonance units are formed between resonance electrodes 6a and 6b formed on one main surface and a common electrode 6c formed on the other main surface. In the region where the two resonance units are configured, the polarization directions of the piezoelectric plates are opposite as shown by the arrows in the figure.

Furthermore, a structure using a four-terminal piezoelectric oscillator shown in FIG. 4 has also been proposed. Here, a resonant electrode is placed on one main surface of the piezoelectric oscillator 7. a, 7b have resonance electrodes 7c, 7d on the other main surface.
is formed to constitute a four-terminal piezoelectric oscillator.

In the piezoelectric oscillator 7, the piezoelectric plate is uniformly polarized as shown in the direction of the illustrated arrow. In this piezoelectric oscillator, lead terminals are actually drawn out from each resonance electrode 7a to 7d, and when mounted on a printed circuit board, the lead terminals connected to resonance electrode 7c and resonance electrode 7b are connected to each other. They are electrically connected by a conductive pattern on a printed circuit board.

[Technical Problem to be Solved by the Invention] In the piezoelectric oscillator 6 shown in FIG. 3, the polarization direction of the piezoelectric plate must be reversed depending on the amount of resonance units. Therefore, a complicated polarization process is required, and it is difficult to obtain an oscillator with stable characteristics.

On the other hand, in the piezoelectric oscillator 7 shown in FIG. 4, since the polarization direction is uniform, the polarization process is easy.

However, it is a four-terminal type piezoelectric component with four lead terminals drawn out, and it is necessary to wire between the lead terminals using a conductive pattern on the printed circuit board, that is, it requires complicated wiring work. In addition, the packaging density also decreases, so it has not been commercialized in reality.

Therefore, an object of the present invention is to provide a piezoelectric resonator with built-in load capacitance that is small and inexpensive and does not require complicated polarization processing or external wiring work.

[Means for Solving Technical Problem I1] The present invention is a chip-type piezoelectric resonator using an energy confinement type piezoelectric resonator, in which a piezoelectric plate is uniformly polarized.

On one principal surface of the piezoelectric plate, a first. A second resonant electrode is formed on the other main surface, and third and fourth resonant electrodes are formed on the other main surface. Third
．． The fourth resonant electrode is the first resonant electrode. The second resonant electrode and the piezoelectric plate are formed so as to face each other at least partially.

The first to fourth resonant electrodes are drawn out to different first to fourth regions of the outer peripheral side surface of the piezoelectric plate.

On the other hand, first to fourth terminal electrodes are formed on the side surface of the piezoelectric plate so as to be electrically connected to the first to fourth resonant electrodes, and the third resonant electrode is electrically connected to the third resonant electrode. A third terminal electrode electrically connected to the fourth resonant electrode and a second terminal electrode electrically connected to the second resonant electrode formed to face the fourth resonant electrode utilize the outer peripheral surface of the component. and are electrically connected.

As the resonant electrode formed on the piezoelectric plate, there are four resonant electrodes on one main surface.
It may also be one in which divided resonant electrodes are formed. That is, on one main surface of the piezoelectric substrate, the first. In addition to the second resonant electrode, a 5.degree. sixth resonant electrode is provided on the other major surface. It is also possible to use a structure in which the seventh and eighth resonant electrodes are formed so as to face the sixth resonant electrode with a piezoelectric plate in between. In this case, the fifth to eighth resonant electrodes are drawn out to the fifth to eighth regions of the outer peripheral side surface, and the fifth to eighth terminals formed in the fifth to eighth regions electrically connected to the electrode. The fourth terminal electrode and the fifth terminal electrode are connected to each other, and the sixth terminal electrode and the seventh terminal electrode are connected to each other.
terminal electrodes are electrically connected to each other using the outer peripheral surface of the component.

[Effect]

Since it uses a piezoelectric plate with a uniform polarization direction, it does not require complicated polarization processing, and since the second and third resonant electrodes are pre-wired within the component, it can be easily attached to printed circuit boards, etc. When mounting, there is no need to form a wiring pattern on the circuit board, and it is also possible to reduce the mounting space.

[Explanation of Examples]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1(a) is a plan view for explaining a piezoelectric plate used in a piezoelectric oscillator as an embodiment of the present invention and a resonant electrode formed on the piezoelectric plate, and FIG. 1(b) is a FIG. 3 is a plan view showing the shape of the resonant electrode on the lower surface side when seen through the piezoelectric plate. The piezoelectric plate 11 is made of piezoelectric ceramics that are polarized uniformly in the thickness direction. At the center of the upper surface of the piezoelectric plate 11, there is a first resonant electrode 12 having a substantially semicircular shape that is divided into two parts.
a and a second resonant electrode 12b are formed. The first resonant electrode 12a and the second resonant electrode 12b are connected to the first side surface 11a and the second side surface 11b of the piezoelectric plate 11, respectively.
The electrodes 13a and 13b extend up to the point where they are drawn out.

On the other hand, as shown in FIG. 1(b) through the piezoelectric plate 11, a substantially semicircular third resonant electrode 12c and a fourth resonant electrode 12d are formed on the lower surface of the piezoelectric plate 11. ing. The third resonant electrode 12C is the first resonant electrode 12a.
Similarly, the fourth resonant electrode 12d is formed to face the second resonant electrode 12b with the piezoelectric plate 11 in between. The third and fourth resonance electrodes 12c and 12d are connected to the third side surface 11 of the piezoelectric plate 11 by extraction electrodes 13c and 13d, respectively.
c and the fourth side lid.

When manufacturing the piezoelectric plate 11, it is only necessary to prepare a piezoelectric plate that has been polarized uniformly in the thickness direction, so there is no need for complicated polarization treatment. a resonant unit composed of third resonant electrodes 12a and 12c;
Fourth resonant electrode 12b.

Differences in resonance characteristics from the resonance unit composed of 12d are also unlikely to occur.

Next, protective substrates 14a and 14b made of insulating ceramics shown in FIG. 5 are bonded to the upper and lower surfaces of the piezoelectric plate 11 via an adhesive. In this way, the resonant portion can be sealed.

Although not particularly shown, a recess is formed on the upper or lower surface of the protective substrates 14a, 14b in order to provide a space for not interfering with the resonance of the portion where the resonance unit is formed.

In addition to insulating ceramic straw, the protective substrates 14a and 14b may be made of glass, high melting point #A resin that can withstand the heat during soldering or electrode formation, or even a metal plate coated with insulation. It may be composed of

Next, the piezoelectric plate 11 on which the protective substrates 14a and 14b are laminated
The first to fourth terminal electrodes 1 are disposed in the first to fourth regions on the side surface of the
5a to 15d are formed. Terminal 1fi15a~15d
is formed by applying and baking a conductive paste, or by a known electrode forming method such as plating or vapor deposition.

The first terminal electrode 15a is connected to the first resonant electrode 12a (first
(Figure) and is used as an input/output terminal electrode. Further, the fourth terminal electrode 15d is electrically connected to the fourth resonant electrode 12d, and is also used as an input/output side terminal electrode.

On the other hand, the second. The third terminal electrodes 15b and 15c are connected to the second terminal electrodes 15b and 15c, respectively. It is electrically connected to the third resonant electrodes 12b and 12c, and is electrically connected to each other by a connecting electrode 16.

Therefore, in the piezoelectric oscillator described above, the terminal electrode 15a.

It can be seen that the piezoelectric oscillator with built-in load capacitance shown in the equivalent circuit in FIG. 6 is constructed, with 15d as the input/output terminal, terminal 1 as the pole 15b, and pole 15c as the ground terminal. Moreover, as in the case of the conventional piezoelectric oscillator 7 shown in FIG. 4, it is not necessary to perform complicated wiring work outside the piezoelectric oscillator, which improves mounting workability and reduces mounting space. It is also possible.

Note that the formation of the pressure till described above and the protection substrates 14a, 1
The steps such as lamination 4b can be performed in the state of the motherboard, and therefore the piezoelectric component of the above embodiment is excellent in mass production. Further, in the above embodiment, the second.
The terminal electrodes 15b and 15c connected to the third resonant electrode were electrically connected by the connection electrode 16 formed on the protective substrate 14a, but the second. The electrical connection of the third resonant electrode may be made at any arbitrary portion such as the side surface of the piezoelectric plate 11 or the lower surface of the protective substrate 14b.

FIGS. 7(a) and 7(b) are a plan view for explaining another example of the common IT pole shape that can be used in the present invention, and a plan view for explaining the shape of the resonant electrode on the lower surface side as seen through the piezoelectric plate. This is a diagram.

Here, the first and second resonant electrodes 12a and 12b formed on the upper surface of the piezoelectric plate 11 have a shape obtained by diagonally dividing a circular electrode material. On the lower surface side of the piezoelectric plate 11,
Third. Fourth resonant i-pole 12c.

12d are the first . Second resonant electrode 12a, 1
It is formed so as to overlap with 2b.

The second difference from the embodiment shown in FIG. 1 is that the arching electrodes 13b, 13c are drawn out to the same side surface 11b. The piezoelectric oscillator shown in FIG. 8 can be obtained by laminating protective substrates 14a and 14b on the upper and lower surfaces of the piezoelectric plate 11 shown in FIG. 7 and forming terminal electrodes. Here, the first to third terminal electrodes 16a to 16c are formed by a known external electrode forming method, and the terminal electrode 16a.

16c respectively connect the input and output terminal electrodes to f#I. The second resonance electrode 1i1tfi 12b and the third resonance electrode 12c in FIG. 7 are electrically connected by the terminal electrode 16b. Extraction electrode 13b.

13C (FIG. 7) was drawn out to the same side surface 11b, in this embodiment, the second. A third resonant electrode is connected.

In the embodiments described above, a piezoelectric oscillator using an energy trapping type piezoelectric resonator utilizing a thickness longitudinal vibration mode in which resonant electrodes are formed on both principal surfaces of a piezoelectric plate polarized in the thickness direction has been described. However, it is also possible to use piezoelectric resonators that utilize other vibration modes.

FIGS. 9(a) and 9(b) show an example in which the present invention is applied to an energy confinement type piezoelectric resonator using a thickness shear vibration mode.

The piezoelectric resonator 21 uses a rectangular piezoelectric plate 22 that is uniformly polarized in the direction of the illustrated arrow. Piezoelectric plate 2
2 has a first section extending in the longitudinal direction. Second resonant electrodes 23a and 23b are formed to extend from the side surface 22a of the piezoelectric plate 22 toward the center. On the other hand, piezoelectric plate 2
2, there is a third side extending from the side surface 22b on the other side toward the center. Fourth resonant electrodes 23c and 23d are formed. That is, it can be seen that in the piezoelectric resonator 21 of this example as well, the piezoelectric plate 22 is uniformly polarized, and two divided resonant electrodes are formed on both principal surfaces. Therefore, from the outer peripheral side surface of the piezoelectric plate 22, four areas that are not short-circuited to each other are selected and
forming a fourth terminal electrode; By electrically connecting the third terminal electrode on the outer peripheral surface of the component, a piezoelectric oscillator with built-in load capacitance similar to the first embodiment can be constructed.

FIG. 10 is a perspective view showing another example of an energy confinement type piezoelectric resonator using a thickness shear vibration mode that can be used in the present invention, and a view showing a resonant electrode on the lower surface side.

In the piezoelectric resonator 31, from the center of the top surface of the piezoelectric plate 32 to the side surface 3
1° second resonance electrode 3 extending toward 2a, 32b side
3a and 33b are formed.

On the other hand, as shown in FIG. 10(b), a space 34b is opened on the lower surface side that is wider than the space 34a between the resonant electrodes 33a and 33b on the upper surface side, and the third and fourth resonant electrodes 33
c, 33d are formed.

Note that the first to fourth resonant electrodes 33a to 33d are drawn out to side surfaces 32a and 32b of the piezoelectric section 32 by lead electrodes 35a to 35d, respectively.

The piezoelectric resonator 31 in FIG. 10 corresponds to a structure in which two piezoelectric resonance units in the piezoelectric resonator 21 shown in FIG. 9 are joined in the longitudinal direction of a piezoelectric plate. Therefore, by forming the first to fourth terminal electrodes on the side surface portion of the piezoelectric plate 32 from which the above-mentioned extraction electrodes 35a to 35d are extracted,
It can be seen that a piezoelectric oscillator similar to that of the above embodiment can be constructed.

FIGS. 11(a) and 11(b) are plan views for explaining still another embodiment of the present invention. In the piezoelectric resonator 41 of this embodiment, the first... In addition to the second resonant electrodes 12a, 12b, a fifth. Sixth resonant electrode 43
a, 43b are formed. Further, on the other main surface of the piezoelectric plate 42, a 5° 7.degree. Eighth resonant electrodes 43c and 43d are formed.

That is, in the piezoelectric resonator 41, resonance electrodes each having a shape obtained by dividing a circular electrode material into four parts are formed on both main surfaces of the piezoelectric plate 42.

First to eighth resonant electrodes 12a to 12d, 43a to 43d
are lead electrodes L3a-13d, 44a to 44a, respectively.
44d, it is drawn out to the first to eighth regions of the outer peripheral side surface of the pressure tt plate 42.

However, among the above-mentioned extraction electrodes, the extraction electrode 13b connected to the second resonant electrode 12b and the third resonant electrode 12c
The lead electrode 13c connected to the piezoelectric plate 42 is drawn out to the central region of the same side surface 42a of the piezoelectric plate 42. That is, the above 2. The third region is the -N region. Similarly, the extraction electrode 44a and the extraction electrode 13d are on the same side 42b.
The extraction electrode 44b and the extraction electrode 4
4c is drawn out in the central area of the same side 42c.

Therefore, as in the embodiment shown in FIG.
If a terminal electrode extending in the thickness direction of the piezoelectric plate 42 is formed on a, the extraction electrode 13b and the extraction electrode 13c can be electrically connected, whereby the second resonant electrode 12
b and the third resonant electrode 12c can be electrically connected.

Similarly, by similarly forming terminals on the other side surfaces 42b and 42c of the piezoelectric plate 42,
The fifth resonant electrode 43a and the fourth resonant electrode 12d, and the sixth resonant electrode 43b and the seventh resonant electrode 43c can be electrically connected to each other. In this way, the 11th
By using the piezoelectric resonator 41 shown in the figure, it is possible to easily obtain a resonator device having a structure in which a plurality of structures shown in the equivalent circuit shown in FIG. 6 are electrically connected.

It should be pointed out that the piezoelectric resonator of the present invention is not limited to being used to enhance the piezoelectric oscillation circuit described above, but can be applied to filters and various resonant devices.

[Effects of the Invention] As described above, in the present invention, since the piezoelectric plate is only uniformly polarized, there is no need to implement a complicated polarization method such as partially polarizing in the opposite direction. . Further, since the load capacitance can be configured without requiring an external capacitor or the like, the configuration of the piezoelectric oscillation circuit can be made simple and compact. Since it is configured as a chip-type component that can be connected appropriately using the outer peripheral surface of the element using the first to fourth terminal electrodes, complicated wiring work on printed circuit boards, etc. can be omitted, and the mounting space can also be reduced.

Further, a fifth plate is provided on one main surface of the piezoelectric plate. A sixth resonant electrode is disposed on the other main surface of the seventh resonant electrode. An eighth resonant electrode is further formed and drawn out to the outer circumferential side of the piezoelectric plate, and the connection between the second to seventh resonant electrodes is the same as the third terminal electrode in the example in which only the first to fourth resonant electrodes are formed. By electrically connecting using the outer peripheral surface of the component in the same manner as the second terminal electrode, it becomes possible to realize the f# power of a more complicated piezoelectric resonant circuit with a small chip component.

[Brief explanation of drawings]

FIGS. 1(a) and 1(b) are a plan view for explaining the shapes of a piezoelectric plate and a resonant electrode used in the first embodiment of the present invention, and a resonance on the lower surface side seen through the piezoelectric plate, respectively. Figure 2 is a diagram showing the electrode shape, Figure 2 is a diagram showing an oscillation circuit, Figure 3 is a circuit diagram showing an oscillation circuit using a conventional piezoelectric oscillator, and Figure 4 explains another example of a conventional piezoelectric oscillator. Schematic diagram for
FIG. 5 is an external perspective view of the first embodiment of the present invention, FIG. 6 is a diagram showing an equivalent circuit of the first embodiment of the present invention, and FIG.
) and (b) are respective plan views for explaining the resonant electrode shape in the second embodiment of the present invention, FIG. 8 is an external perspective view of the second embodiment, and FIGS. 9 (a) and (b). ) are respectively,
A perspective view and a sectional view taken along line B-B for explaining another example of a piezoelectric resonator to which the present invention can be applied, FIG. 10(a)
and (b) are a perspective view for explaining still another piezoelectric resonator that can be used in the present invention, a schematic plan view showing a resonance electrode formed on the lower surface side, and FIG.
) and (b) are plan views for explaining still other examples of the present invention, respectively, in which 11 is a piezoelectric plate, lla to lid are first to fourth side surfaces, and 12a to 12d.
15a to 15d indicate first to fourth resonance 'I1g+, and first to fourth terminal electrodes.

Claims (2)

[Claims] (1) An energy-trapping chip-type piezoelectric resonator comprising: a uniformly polarized piezoelectric plate; first and second resonant electrodes formed on one main surface of the piezoelectric plate; The other main surface of the piezoelectric plate is provided with first and second resonance electrodes and third and fourth resonance electrodes formed so as to face each other at least partially with the piezoelectric plate interposed therebetween, The first to fourth resonance electrodes are drawn out to first to fourth regions of the outer peripheral side surface of the piezoelectric plate, and are formed in the first to fourth regions of the outer peripheral side surface of the piezoelectric plate, 1st~
The device further includes first to fourth terminal electrodes each electrically connected to the fourth resonant electrode, and the third terminal electrode and the second terminal electrode are electrically connected using the outer peripheral surface of the component. A chip-shaped piezoelectric resonator. (2) fifth and sixth resonant electrodes are formed on one main surface of the piezoelectric plate in addition to the first and second resonant electrodes;
Seventh and eighth resonant electrodes are formed on the other main surface so as to face the fifth and sixth resonant electrodes, respectively, with a piezoelectric plate interposed therebetween. The electrodes are drawn out to the fifth to eighth regions of the outer circumferential side surface of the piezoelectric plate, are formed in the fifth to eighth regions of the outer circumferential side surface of the piezoelectric plate, and are formed in the fifth to eighth regions of the outer circumferential side surface of the piezoelectric plate. Further comprising fifth to eighth terminal electrodes each electrically connected to the resonant electrode, wherein the fourth terminal electrode and the fifth terminal electrode are connected to a sixth terminal electrode.
The chip-type piezoelectric resonator according to claim 1, wherein the terminal electrode and the seventh terminal electrode are electrically connected using the outer peripheral surface of the component.